ASPNET Unit Testing — Unit Testing ASP.NET Core Components

public class ScanServiceTests
{
    [Fact]
    public async Task ScanAsync_WithCleanFile_ReturnsCleanResult()
    {
        var mockEngine = new Mock<IScanEngine>();
        mockEngine.Setup(e => e.AnalyzeAsync(It.IsAny<byte[]>()))
            .ReturnsAsync(new AnalysisResult { IsThreat = false });

        var mockLogger = new Mock<ILogger<ScanService>>();
        var service = new ScanService(mockEngine.Object, mockLogger.Object);

        var result = await service.ScanAsync(new ScanRequest { FileName = "test.txt", Content = new byte[50] });

        Assert.NotNull(result);
        Assert.Equal("clean", result.Status);
        Assert.Empty(result.Threats);
    }

    [Fact]
    public void ScanRequestValidator_InvalidFileSize_ReturnsError()
    {
        var validator = new ScanRequestValidator();
        var request = new ScanRequest { FileName = "huge.bin", Content = new byte[100_000_001] };

        var result = validator.Validate(request);

        Assert.False(result.IsValid);
        Assert.Contains(result.Errors, e => e.PropertyName == "Content");
    }
}